This invention relates to an improved and an economical process to convert biomass containing lignin-cellulose into water soluble hemicellulose, carbohydrates, lignin, lignin-cellulose resinous products, tall oil, turpentine and CO2. In U.S. Pat. No. 4,321,360 issued Mar. 22, 1982 to David H. Blount, M. D., it illustrated the process to break-down cellulose-containing plants into water-soluble polymers, but did not include the production of ethanol, lignin resinous products and the recover of the alkali metal catalyst. Other inventors have utilized acids to break down the cellulose to carbohydrates or may use an alkali metal hydroxide to separate the lignin from cellulose then using an acid such as sulfuric acid to break down the cellulose to carbohydrates. In the improved process of this invention, the biomass is first mixed and wet with the recovered aqueous alkali metal hydroxide in order to distribute the alkali metal catalyst though out the biomass and break the lignin-cellulose bond. The alkali metal hydroxide is used in a sufficient amount to produce a thermal reaction. This reaction removes carbon dioxide from the cellulose to produce carbohydrates and from the lignin to produce a modified lignin. This process also differs from U.S. Pat. No. 4,321,360, because in the process of evaporating off the excess water the lignin-cellulose bond is broken, then when the biomass is further heated the cellulose is converted to carbohydrates by the loss of carbon oxide bonds and carbon dioxide is produced. This method is an improvement because over 90% of the biomass is converted to water soluble material and the yield of carbohydrates is greatly increased over that produced by the method of U.S. Pat. No. 4,321,360. Alcohol and a more chemically active modified lignins are produced, and also heat, water, alkali metal catalyst and alkaline earth metal oxide are recovered for reuse. When the method of this invention is compared to other methods using alkali catalyst, there is a utilization of much less energy for heating the reactants, because the reaction between the dried alkali metal hydroxide and cellulose is exothermic due to the higher ratio of the alkali metal hydroxide to the cellulose used in other methods. The heat produced by the exothermic reaction is used for other processes of this invention. This higher ratio of alkali metal hydroxide produces a greater yield of carbohydrates from the biomass. The alkali metal hydroxide is recover to be reused in this process.
The carbohydrates produced by this process may be utilized to produce ethanol by fermentation, used as a food for animals and humans or utilized to produce polyols for urethane production. The modified alkali metal lignin, modified lignin, lignin-cellulose resinous products, carbohydrates and hemi-cellulose may be further reacted with organic epoxides, mono- and polysubstituted organic compounds, aldehydes or reacted with amino compounds and/or phenol and aldehydes to produce new and useful products. The lignin-cellulose resinous material or alkali metal lignin-cellulose resinous products may be used as an adhesive such as in producing plywood, in laminates, as filler, etc., and may be further reacted with aldehydes, aminoplasts, phenoplasts, epoxides, ketones, furfuryl alcohol, amines, isocyanates, polyamines, polyisocyanates, mono- and polysubstituted organic compounds such as polyhalides, monohalides organic anhydrides, epihalohydrins, halohydrins and other organic compounds to produce useful resins which may be utilized as adhesives, as laminates as coating agents, as molding agents, as foams. The lignin-cellulose resinous products are soluble in common organic solvents such as ketones, alcohols, glycols, organic esters, etc.
Lignin-cellulose resinous products, modified lignin, carbon dioxide, turpentine, tall oil, carbohydrates and alcohol are produced by reacting the following components:
Component (a): A biomass of lignin-cellulose or cellulose containing plant;
Component (b): An aqueous alkali metal hydroxide;
Component (c): An acidic salt-producing compound;
Component (d): Fermentation agent;
Component (e): Alkaline earth metal oxide or hydroxide;
Component (f): water.